1. Field of the Invention
The invention relates to a driving device for printing machines, having a rod for moving a distributor roller reciprocatingly in axial direction.
German Patent 18 51 98 describes such a device, wherein an inking roller is seated rotatably on a shaft firmly mounted in the frame. A connecting rod extending into the interior of the inking roller transmits the movement of a journal to the inking roller.
It is an object of the invention to provide a driving device for printing machines which is considerably improved over corresponding devices heretofore known in the art.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a driving device for printing machines, having a rod for oscillatingly moving a distributor roller in axial direction, comprising a joint via which the rod is connected to the distributor roller, the joint permitting relative movement between the rod and the distributor roller so as to compensate for a displacement of the distributor roller perpendicularly to the axial direction of the distributor roller.
In accordance with another feature of the invention, the joint has at least two degrees of freedom.
In accordance with a further feature of the invention, the joint is a self-aligning bearing.
In accordance with an added feature of the invention, the joint is disposed in the distributor roller.
In accordance with an additional feature of the invention, the joint is disposed approximately at the center of mass of the distributor roller.
In accordance with yet another feature of the invention, the rod is couplable via a readily releasable connection to a transmission element for reciprocatingly moving the distributor roller in axial direction.
In accordance with yet a further feature of the invention the connection is a plug-in connection.
In accordance with an alternative feature of the invention, the connection is a snap-in connection.
In accordance with yet an added feature of the invention, the connection is located outside the distributor roller.
In accordance with a concomitant aspect of the invention, there is provided a printing machine having a driving device provided with at least one of the foregoing features.
The driving device according to the invention is distinguished by the fact that the rod and the distributor roller are connected to one another via a joint which permits relative movement between the rod and the distributor roller if the distributor roll is displaced perpendicularly to the axial direction thereof.
The advantageous feature of the driving device according to the invention is that the distributor roller is entrainable together with two applicator rollers towards and away from a plate cylinder, without losing the rolling contact between the distributor roller and the two applicator rollers during the displacement.
In one embodiment of the invention, which is advantageous with regard to the ability of the middle axis of the distributor roller to be pivoted, the joint is rotatable about at least two ideal axes of rotation, one of which extends coaxially with the middle axis of the distributor roller, and the other extends transversely to the middle axis of the distributor roller.
In an embodiment which is advantageous with regard to any desired skewed positions of the distributor roller relative to the rod, the joint has three degrees of freedom or ideal axes of rotation. Such a joint is, for example, a self-aligning or pivot bearing, which permits pivoting movements of the distributor roller in all planes wherein the middle axis is located.
In an embodiment which is advantageous with regard to a space-saving compact construction of the driving device, the joint is disposed in the interior of the distributor roller.
In an embodiment which is advantageous with regard to the constancy of the widths of the press strips formed by the distributor roller together with the applicator rollers over the roller lengths, the joint, as viewed in the axial direction of the distributor roller, is disposed approximately in the middle thereof.
In an embodiment which is advantageous with regard to the simple removal of the distributor roller from the printing machine for roller maintenance, at the end of the rod opposite or distal from the joint, the rod is connected by a readily releasable connection to a transmission element which reciprocatingly moves the rod and, via the latter, the distributor roller. The reciprocatory movement of the rod is transmitted to the distributor roller by the joint, which in this case functions not only as a radial bearing but also as an axial bearing. Before removing the distributor roller, the pressman can release the connection, if desired, and make the connection once again after the reinsertion of the distributor roller.
In an embodiment which is advantageous with regard to a positive or form-locking coupling of the transmission element to the rod, the connection is a plug-in connection. In this regard, it is noted that a form-locking connection is one which connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements.
In an embodiment which is advantageous with regard to making and releasing the connection without any tools, the connection is not only a plug-in connection but also a snap-in connection.
In an embodiment which is advantageous with regard to good accessibility of the connection when it is being made and released, that end of the rod at which the connection is located projects out of the interior of the distributor roller.
The driving device is preferably a constituent part of an inking unit of a rotary offset printing machine.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a driving device for printing machines, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.